I. Field of the Invention
This invention relates in general to improvements in flush valves for water closets, urinals, and other plumbing equipment. More particularly, the invention relates to an improved diaphragm for use in flush valves.
II. Description of the Related Art
Flush valves in water closets, urinals, and other plumbing devices which utilize a flexible diaphragm to establish and to seal off the connection between the inlet and outlet are well-known in the art. FIG. 1 illustrates a typical prior art flush valve and diaphragm assembly. The flush valve has a hollow body 10, generally made of brass, which includes an inlet connection 12, an outlet connection 14, and a handle connection 16. Barrel 18 is positioned within the flush valve such that the connection between inlet 12 and outlet 14 is through barrel 18. An annular main valve seat 20 is formed on the top of the barrel 18 Annular main valve seat 20 is normally closed by diaphragm 22 extending across body 10 and defining an upper chamber 24. Diaphragm 22 has a bypass 26 which provides fluid communication between the inlet side of the flush valve and upper chamber 24. Diaphragm 22 is attached at its outer edge to the valve body and is clamped in place by an annular clamping rim on the outer cover 11 of body 10. The center of diaphragm 22 has an opening which allows for fluid communication between upper chamber 24 and outlet 14. A relief valve 28 normally closes the opening at the center of the diaphragm.
The operation of the flush valve is generally as follows. In the normally closed position shown in FIG. 1, water pressure at the valve inlet is communicated to upper chamber 24 through bypass 26. Since the surface area which is subjected to water pressure is greater on the upper side of diaphragm 22, the water pressure forces diaphragm 22 down onto valve seat 20 preventing water from flowing to outlet 14. When the user moves the handle 30 in any direction, the plunger 32 moves inwardly tilting the stem 34 of relief valve 28. This releases the pressure in upper chamber 24 by allowing water to flow through a guide member 36. With the upper chamber pressure relieved, the inlet water pressure forces diaphragm 22 upwardly, off main valve seat 20 allowing water to flow directly from inlet 12 through barrel 18 to outlet 14. When diaphragm 22 and relief valve 28 move upwardly, relief valve 28 resets itself, closing off upper chamber 24. Water will then flow through bypass 26 into upper chamber 24 until diaphragm 22 is again forced against main valve seat 20, thereby closing the valve. Guide member 36 moves with diaphragm 22 and includes outwardly extending radial wing members 38 which engage the inner surface of barrel 18 to guide the guide member 36 and attached diaphragm 22 as diaphragm 22 moves up and down.
The diaphragm assembly of the prior art device comprises diaphragm 22, relief valve 28, stem 34, guide member 36, wing members 38, retaining disc 40, as well as the flow ring 42. This prior art diaphragm assembly suffers from several distinct disadvantages.
Diaphragm 22 uses diaphragm tabs and rings to lend rigidity to the otherwise extremely flexible rubber parts. The rigidity of diaphragm 22 is critical to performance. Retaining disc 40 utilizes brass threads to attach the diaphragm 22 to guide member 36. Within diaphragm 22 rubber is bonded to the brass parts to obtain acceptable seating surfaces. This combined use of rubber and brass for the diaphragm 22 and the retaining disc 40 increases manufacturing costs and assembly time.
The multi-piece prior art diaphragm assembly results in tolerance stack-up variations leading to flow variations between different valves. This prior art device allows for separation of the diaphragm tab from the diaphragm rubber, resulting in the shortening of the diaphragm life. Furthermore, the separation of the diaphragm tab creates rubber particles which may clog bypass 26.
U.S. Pat. Nos. 4,817,913, 4,883,254, 4,913,182 and 4,968,067, all to Whiteside, disclose a substantially unitary diaphragm assembly. However, the diaphragm assemblies of these devices are utilized with a different valve assembly such that the diaphragm assembly does not include a flow ring, retaining disc or wing members. Furthermore, the diaphragm assembly of Whiteside requires the utilization of a redesigned relief valve.
The object of the present invention is to overcome the above-identified drawbacks of the prior art by utilizing an improved diaphragm assembly to control the flow parameters of a flush valve which flushes, rinses and refills water closets and urinals in a consistent, quiet, quick and effective manner. The object of the present invention is to provide a diaphragm assembly which may be utilized with a common valve assembly.